Improvement in safety-valves



T. SHAW. SAFETY-VALVE.

No. 193,558. Patented July 24,1877.

'INVENTOR UNITED STATES PATENT QTTTGE.

THOMAS SHAW, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEM ENT IN SAFETY-VALVES.

Specification forming part of Letters Patent No. 193,558, dated July'24, 1877; application filed July 3, 1877.

To all whom it may concern:

Be it known that I, THOMAS SHAW, of the city and county of Philadelphia,Pennsylvania, have invented a new and Improved Mode ot'Arresting,Vibrating, and Pounding Motion of Safety-Valves; and I hereby declarethe following to be a full, clear, and exact description of the same,reference being had to the accompanying drawing, and to the letters ofreference marked thereon.

My invention consists in the application of slight frictional resistanceto the valve, in the manner and for the purpose as hereinafterdescribed.

The object of the invention is to prevent that disagreeable hammeringsound that frequently occurs in the class of safety-valves known aspop-valves.

In order to enable others to use and practice my invention, I willproceed to describe its construction and operation.

On reference to the accompanying drawing, which forms part of thespecification, the sketch represents a vertical section through centerof valve and valve-seat, &c., of which A is the main body of the valveprovided with a screw-thread at O, for attachment to boiler, and withscrew-thread at B for attachment to usual spring portion ofvalve-rigging. D is the central opening for the passage of steam to thevalve proper G, which is constructed onthe pop-valve principle, havingthe enlarged face J above the valve-seat I, and is provided with theusual guide-wings E and with the concave top H, for the reception of thecone or lower portion of the ordinary spring. (Not shown.) F is agroove, cut in Wings E for the inserting of a wire ring arranged tospring against the walls of the body of the valve A with just enoughforce to create a slight but constant friction, which I have foundsufficient to arrest all hammering or pounding action occasioned by therapid vibrations of valve, which vibrations are induced by the rapidsuccessive spurts of steam against the enlarged face area of popvalves.

It will be evident that the spring-action of the wire insures a constantapplication of frictional resistance, however slight, and that thisforce may be variously applied to different portions of the valvewithout any alteration in the result. I therefore do not wish to confinemyself to the exact shape or location of the resisting-spring medium forthe purpose described; but

What I do claim, and desire to secure by Letters Patent, is

1. A safety-valve provided with a spring, substantially as described,whereby the hammering of the valve incident upon the escape ofhigh-pressure steam is prevented.

2.. In a safety-valve, a spring surrounding the guide-Wings of thevalve, as and for the purpose set forth.

3. A valve having its guide-wings recessed to receive a spring, as andfor the purpose set forth.

4. The combination, in a safety-valve, of the casing A, valve G,- havingrecesses in the guide-win gs, and a spring placed within such recess, asand for the purpose set forth.

- THOMAS SHAW. Witnesses:

ELIAS J. SHAW, WM. B. HUGHES.

